It’s been awhile since I reviewed science podcasts on the Internet. So I spent a few hours listening to shows, which are basically audio programs you can listen to on your computer or download to an MP3 player or an iPod.

The number of shows is growing like crab grass. Some are good. Most are mediocre. Some are truly weird. Here’s a tiny sample of what’s available from the directories of www.podcast.net and www.apple.com/itunes.

THE MATH FACTOR: I’m so bad at math I need Microsoft Money to balance my checkbook. But I love the “Factor,” which is produced by KUAF/91.3 in Fayetteville, Ark. A recent show asked: When will we run out of Social Security numbers? About 420 million numbers have been issued so far. An additional 5.5 million a year are given out. At that rate, says the show, it’ll take a century to run out of numbers. The show also asked: How can a person be of average height and average weight and still be regarded as overweight? You’ll have to listen to the “Factor” to find out.

HMM … KRULWICH ON SCIENCE: I don’t believe in asking for autographs. But I made a point a few years ago of meeting National Public Radio’s Robert Krulwich to tell him how much I admire his ability to tell a compelling story about virtually any aspect of science. You’ll know what I mean if you heard the recent podcast in which he explained how and why the number of cells in the human body is dwarfed by bacteria. Or if you listened to him get former astronaut Dan Barry to explain how he coped with the mosquitoes that stowed away on the space shuttle. Krulwich is the best conversationalist in science.

ABSOLUTE SCIENCE: Co-hosts Mignon Fogarty and Adam Lowe are as bland as rice cakes. But their show is topical and worth a listen. They responded to the heat waves that have scorched the United States this summer by explaining the importance of sweating in humans. I was surprised to learn that certain medications, such as antidepressants, can interfere with sweating, affecting people’s health. “Absolute” also sometimes features decent interviews, including a recent talk with David Foster, a writer for the TV medical drama “House.” Foster explained how the show sometimes “cheats” on accuracy. Now there’s a surprise.

SHRINK RAP RADIO: Catchy title, boring show. It’s hosted by a guy who identifies himself as Dr. Dave, the dude who “speaks from the “psychologist in me to the psychologist in you.” His full name is David Van Nuys. He’s a professor emeritus of psychology from Sonoma State University. And he’s a bit of a name dropper. Dr. Dave is also a poor interviewer. Last week, he failed to get Judith E. Glaser, author of “The DNA of Leadership” to clearly explain the premise of her book. Complete waste of time.

MR. SCIENCE SHOW: Another catchy title. This podcast is a bit better than Dr. Dave. But only a bit. Host Marc West, who produces the show from Sydney, Australia, referred to physicist Stephen Hawking as “that wheelchair guy.” How’s that for insensitive? But West gave an interesting explanation of how Hawking, who suffers from amyotrophic lateral sclerosis, uses computers to communicate. West also offered a thoughtful take on attempts by scientists to create cloaking devices, making objects essentially invisible. Unfortunately, his talk was almost overwhelmed by loud, boring background music, a common problem in podcasting.

SLACKER ASTRONOMY: The show’s title is misleading. There are no slackers on this program. Instead, you get clear, fascinating analysis of the latest news in astronomy and astrophysics. Yeah, there’s some lame humor. But “Slacker” provided one of the best explanations I’ve heard about the discovery of huge water plumes on Enceladus, one of the moons of Saturn. And recent guests have included people such as Keith Cowing, creator of the privately run Web site NASAWatch, which has better inside information about the space agency than most large mainstream news organizations. The real NASA rarely produces podcasts of such high quality.

SCIENCEDUDE: Today’s blog features an interview with Steve Lindsey, commander of the recent shuttle Discovery flight. Sunday’s edition looks at the week ahead in science and contains a video report. Go to blogs.ocregister.com/sciencedude

NEWS QUIZ ANSWERS

1. Sea surface temperatures are cooling.

2. Nacreous clouds, also known as “mother of pearl” clouds.

3. Obesity

4. Chris

5. Thomas Reiter

Contact the writer: Register science editor Gary Robbins can be reached at 714-796-7970 or grobbins@ocregister.com.